Spindle-Locking Device Viscoelastic Ring Rattle Reduction
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Solution Overview
Problem
Handheld machine tools with spindle-locking devices exhibit nonuniform response behavior and a tendency to rattle due to manufacturing tolerances, gravity, magnetism, and grease adhesion, leading to noise generation and intermittent spindle-lock operation.
Innovation Solution
Incorporation of a viscoelastic ring as an impingement element that impinges on the spindle cylinder with a predefined force, reducing the influence of manufacturing tolerances, gravity, and magnetism, and is situated in a groove on the blocking element or tool housing to enhance response behavior and minimize rattling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a spindle-locking device with spindle cylinders is used to prevent drive spindle rotation, then the drill chuck can be tightened and released using one hand, but the device displays nonuniform response behavior with torsion angles between 6° and more than 360° depending on machine position and braking duration
Solution Approach 1:
The impingement element applies a preliminary counteracting force to the spindle cylinder in the direction of the clamping surface before the spindle-lock operation is fully triggered. This preliminary anti-action compensates for variations in machine position and braking duration, ensuring that the spindle cylinder is consistently pushed against the clamping surface with sufficient force to achieve reliable locking regardless of the drive spindle's rotational state or the tool's orientation.
2Force
If the drive spindle has a great moment of inertia when using heavy tool inserts, then the spindle can handle heavy loads, but the spindle-locking device displays a rattling tendency and may enter intermittent spindle-lock operation resulting in noise generation
Solution Approach 1:
The impingement element continuously applies a counteracting force to the spindle cylinder in the direction of the clamping surface, preventing the spindle cylinder from loosening or oscillating during the drive spindle's run-down phase. This preliminary anti-action counteracts the rattling tendency caused by the great moment of inertia of heavy tool inserts, ensuring stable and continuous spindle-lock operation without intermittent engagement or noise generation.
3Ease of manufacture
If manufacturing tolerances, gravity, magnetism and grease adhesion are present in the spindle-locking device, then the device can be manufactured with standard tolerances, but these factors influence the response behavior of the spindle-locking device
Solution Approach 1:
The impingement element applies a preliminary counteracting force to the spindle cylinder that compensates for the influences of manufacturing tolerances, gravity, magnetism, and grease adhesion. By pushing the spindle cylinder consistently toward the clamping surface with sufficient force, the impingement element ensures that minor variations in manufacturing tolerances and environmental factors do not significantly affect the response behavior or locking reliability of the spindle-locking device.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The viscoelastic ring improves the response behavior of the spindle-locking device and significantly reduces rattling, ensuring a secure and stable application of force, resulting in a robust and cost-effective solution for handheld machine tools.
Implementation Method 1
The impingement element has a viscoelastic ring for impinging on the at least one spindle cylinder
Data Source
AI summary
In a handheld machine tool having a tool housing, in which a drive motor is situated for driving a drive element equipped with at least one clamping surface, to which a spindle-locking device equipped with a blocking element and at least one spindle cylinder is assigned, the at least one spindle cylinder being able to be clamped in a spindle-lock operation of the spindle-locking device between the at least one clamping surface and the blocking element in order to prevent the drive element from rotating relative to the tool housing, the spindle-locking device has an impingement element, which is developed to impinge on the at least one spindle cylinder with a specified force in the direction of the at least one clamping surface.